Previous studies report that high expression of CA IX is correlated with worse outcomes in a variety of cancers, including breast cancer (Koukourakis et al, 2001; Loncaster et al, 2001; Hui et al, 2002; Swinson et al, 2003; Bui et al, 2004; Hussain et al, 2004). This evidence concerns the gene CA9 and breast carcinoma.